A key aspect of a disposable garment is fit over time at use temperature, i.e., the body temperature. Therefore, elastic properties are measured at body temperature to simulate the expected end use conditions. Such garments often include portions which are subject to repeated stretch and relaxation stresses over an extended period of time. Examples include garment materials, pads, wound dressings and wraps, diapers and personal care products where elasticity may be desired. A particular example is the side panel of training pants and incontinence undergarments. This side panel is typically made of an elastic material, often a composite, which can withstand the repeated stretch and resulting stress at body temperature.
At body temperature certain elastic properties of polymers become important. Two specific elastic properties measured are the rate of load decay and the load loss observed over a period of twelve hours at body temperature.
A conventional method of forming such elastic composite material is one in which nonelastic spunbond facing materials are combined with an elastomer layer, comprised of high performance elastic strands. The laminate of the elastic strands is made by; bonding the strand to the facings using a meltblown polymer containing a tackifier and/or a pressure sensitive adhesive. This produces a nonwoven elastic composite with desirable elongations, along with improved mechanical and body conformance properties. This process is sometimes known as a continuous filament stretch bonded laminate ("CFSBL") process.